So-called ‘good bacteria’ that are contained in many popular probiotic drinks are “quite useless,” according to a group of scientists in Israel. Until now, probiotics have been seen as healthy and good for the gut, but the findings of the team from the Weizmann Institute of Science show otherwise. Their study is among the most detailed analyses to date of what happens when we consume probiotics. For their research, the team created a cocktail containing 11 common good bacteria and gave it to 25 healthy volunteers. Samples were then taken from each of the volunteer’s stomachs, as well as their small and large intestines. The scientists were looking to see where the bacteria successfully colonised and whether any changes in the activity of the gut were evident. Publishing their findings in the journal Cell, the scientists said that in half of cases the good bacteria literally went in one end and out the other, without providing any benefits whatsoever. In the rest, they hung around for a bit before being overwhelmed by the bacteria that commonly frequents our bodies. Speaking about the research, Dr Eran Elinav said people should not expect off-the-shelf products to provide them with definitive health benefits. He suggested that the future of probiotics lies in creating bacteria cocktails that are tailored to the specific needs of individuals. “And in that sense just buying probiotics at the supermarket without any tailoring, without any adjustment to the host, at least in part of the population, is quite useless,” he said.